Flea infestation of animals is a health and economic concern because fleas are known to cause and/or transmit a variety of diseases. Fleas directly cause a variety of diseases, including allergies, and also carry a variety of infectious agents including, but not limited to, endoparasites (e.g., nematodes, cestodes, trematodes and protozoa), bacteria and viruses. In particular, the bites of fleas are a problem for animals maintained as pets because the infestation becomes a source of annoyance not only for the pet but also for the pet owner who may find his or her home generally contaminated with insects. As such, fleas are a problem not only when they are on an animal but also when they are in the general environment of the animal.
Bites from fleas are a particular problem because they not only can lead to disease transmission but also can cause a hypersensitive response in animals which is manifested as disease. For example, bites from fleas can cause an allergic disease called flea allergic (or allergy) dermatitis (FAD). A hypersensitive response in animals typically results in localized tissue inflammation and damage, causing substantial discomfort to the animal.
The medical importance of flea infestation has prompted the development of reagents capable of controlling flea infestation. Commonly encountered methods to control flea infestation are generally focused on use of insecticides. While some of these to products are efficacious, most, at best, offer protection of a very limited duration. Furthermore, many of the methods are often not successful in reducing flea populations. In particular, insecticides have been used to prevent flea infestation of animals by adding such insecticides to shampoos, powders, collars, sprays, spot-on formulations foggers and liquid bath treatments (i.e., dips). Reduction of flea infestation on the pet has been unsuccessful for one or more of the following reasons: failure of owner compliance (frequent administration is required); behavioral or physiological intolerance of the pet to the pesticide product or means of administration; and the emergence of flea populations resistant to the prescribed dose of pesticide.
Allantoinase is involved in the catalysis of the reaction converting allantoin to allantoic acid. This is a middle step in purine catabolism, which in insects results in the secretion of urea as the end product. The enzyme is located in the peroxisomes of the liver and kidney in amphibians. There is no known mammalian homologue to allantoinase, as mammals secrete uric acid, a precursor to allantoin. As such, flea allantoinase represents a novel target for anti-flea vaccines and chemotherapeutic drugs. Therefore, isolation and sequencing of flea allantoinase genes may be critical for use in identifying specific agents for treating animals for flea infestation.